To say of any one that he has gray, blue, brown, or black eyes, is vague
and incorrect from a strictly scientific point of view, inasmuch as
there are no really gray or black eyes, and, as a matter of fact, every
eye, if closely examined, shows at least five or six different colours.
There is, first, the tough sclerotic coat or _white_ of the eye, which
covers the greater part of the eyeball, and is not transparent, except
in front where the coloured _iris_ (or rainbow membrane) is seen through
it. This central transparent portion of the sclerotic coat is called the
cornea, and is slightly raised above the general surface of the eyeball,
like the middle portion of some watch-glasses.
The white of the eye is sometimes slightly tinged with blue or yellow,
and sometimes netted with inflamed blood-vessels. All these deviations
are æsthetically inferior to the pure white of the healthy European,
because suggestive of disease, and conflicting with the general cosmic
standards of beauty. The bluish tint is a sign of consumption or
scrofulous disorders, being caused by a diminution of the pigmentary
matter in the choroid coat which lines the inside of the sclerotic. The
yellowish tint, in the European, is indicative of jaundice, dyspepsia,
or premature degeneracy of the white of the eye. It is normal, on the
other hand, in the healthy negro; but if a negro should claim that,
inasmuch as a yellowish sclerotic is to him not suggestive of disease,
he has as much right to consider it beautiful as we our white sclerotic,
the simple retort would be, that we are guided in our æsthetic judgment
by positive as well as negative tests. Disease is the negative test; the
positive lies in the fact that in inanimate objects, where disease is
altogether out of the question—as in ivory ornaments (which no one
associates with an elephant’s tusk)—we also invariably prefer a pure
snowy white to a muddy uncertain yellow. It is these two tests in
combination which have guided Sexual Selection in its efforts to
eliminate all but the pure white sclerotic,—a tint which, moreover,
throws into brighter relief the enchanting hues of the “sunbeamed” iris.
More objectionable still than a yellowish or bluish sclerotic is a
bloodshot eye, not only because the inflamed blood-vessels which swell
and flood the white surface of the eye deface the marble purity of the
sclerotic (in a manner not in the least analogous to marble “veins”),
but because the red, watery blear eye generally indicates the ravages of
intemperance or unrestrained passions. However, a bloodshot eye may be
the result of mere overwork, or reading in a flickering light, or lack
of sleep; hence it is not always safe to allow the disagreeable æsthetic
impression given by inflamed eyes to prognosticate moral obliquity. But,
after all, the intimate connection between æsthetic and moral judgments
is in this case based on a correct, subtle instinct; for is not a man
who ruins the health and beauty of his eyes by intemperance in drink or
night-work sinning against himself? If attempts at suicide are punished
by law, why should not minor offences against one’s Health at least be
looked upon with moral disapproval? If this sentiment could be made
universal, there would be fifty per cent more Beauty in the world after
a single generation.
In the centre of the white sclerotic is the membrane which gives the
eyes their characteristic variations of colour,—the iris or rainbow
curtain. If we look at an eye from a distance of a few paces, it seems
to have some one definite colour, as brown or blue. But on closer
examination we see that there are always several hues in each iris. The
colour of the iris is due to the presence of small pigment granules in
its interior layer. These granules are _always_ brown, in blue and gray
as well as in brown eyes; and the greater their number and thickness,
the darker is the colour of the iris. Blue eyes are caused by the
presence, in front of the pigment-layer, of a thin, almost colourless
membrane, which absorbs all the rays of light except the blue, which it
reflects, and thus causes the translucent iris to appear of that colour.
The Instructions de la Société d’Anthropologie, says Dr. Topinard,
"recognise four shades of colour,—brown, green, blue, and gray; each
having five tones—the very dark, the dark, the intermediate, the light,
and the very light. The expression “brown” does not mean pure brown; it
is rather a reddish, a yellowish, or a greenish brown, corresponding
with the chestnut or auburn colour, the hazel and the sandy, made use of
by the English. The gray, too, is not pure; it is, strictly speaking, a
violet more or less mixed with black and white."
“The negro, in spite of his name, is not black but deep brown,” as Mr.
Tylor remarks; and what is true of his complexion is also true of his
eyes; “what are popularly called black eyes are far from having the iris
really black like the pupil; eyes described as black are commonly of the
deepest shades of brown or violet.”
The pupil, however, is always jetblack, not only in negroes, but in all
races. For the pupil is simply a round opening in the centre of the iris
which allows us to see clear through the lens and watery substance of
the eyeball to the black pigment which lines its inside surface. The
iris, in truth, is nothing but a muscular curtain for regulating the
size of the pupil, and thus determining how much light shall be admitted
into the interior of the eye. When the light is bright and glaring, a
little of it suffices for vision, hence the iris relaxes its fibres and
the pupil becomes smaller; whereas, in twilight and moonlight, the eye
needs all the light it can catch, so the muscles of the iris-curtain
contract and enlarge the pupil-window. This mechanism of the iris in
diminishing or enlarging the pupil can be neatly observed by looking
into a mirror placed on one side of a window. If the hand is put up in
such a way as to screen the eye from the light, the pupil will be seen
to enlarge; and if the hand is then suddenly taken away, it will
immediately return to its smaller size. For the muscles of the iris have
the power, denied to other unstriped or involuntary muscles, of acting
quite rapidly.
Thus we find in the eyeball three distinct zones of colour—the white of
the eye, sometimes slightly tinted blue, yellow, or red; the iris, which
has various shades of brown, green, blue, and gray, commonly two or
three in each eye; and the central black pupil. Add to this the
flesh-colour of the eyelid and surrounding parts, and the light or dark
lashes and eyebrows, and we see that the eye in itself is a perfect
colour-symphony.
Can we account for the existence of all these colours? The easiest thing
in the world, with the aid of the principles of Natural and Sexual
Selection. There are reasons for believing that the sense of sight is
merely a higher development from the sense of temperature, adapted to
vibrations so rapid that the nerves of temperature can no longer
distinguish them. In its simplest form, among the lowest animals, the
sense of sight is represented by a mere pigment spot. And in the highest
form of sight, after the development of the various parts of our
complicated eye, we still find this pigment as one of the most essential
conditions of vision. Its function, however, is not the same as that of
the pigment in the human skin. There it is interposed between the sun
and the underskin, in order to protect the nerves of temperature. The
optic nerve needs no such protection; for the heat-rays of the sun
cannot but be cooled on passing through the membranes, the lens, and the
watery substance in the eye, before reaching the optic nerve, spread out
on the retina. Consequently the eye-pigment, instead of being placed in
front of the nerves, is put behind them; and their function is to absorb
any excess of light that enters the eye. Were the membrane which
contains this pigment whitish, all the light would be reflected back,
and create such a glare and confusion that no object could be seen
distinctly.
This view regarding the function of the pigment is strikingly supported
by the anomalous case of Albinos. “The pink of their eyes (as of white
rabbits) is caused by the absence of the black pigment,” says Mr. Tylor,
“so that light passing out through the iris and pupil is tinged red from
the blood-vessels at the back; thus their eyes may be seen to blush with
the rest of the face.”
Bearing these facts in mind, it is obvious why it is an advantage in a
sunny country to have as much pigmentary matter as possible in the eye,
and why, therefore, Natural Selection makes the eyes blacker the nearer
we approach the tropics. And, as with the complexion, so here, it is
fortunate for the negro that he has not sufficient taste to feel the
æsthetic inferiority of the monotonous black thus imposed on him by
Natural Selection. “The iris is so dark,” says Figuier, “as almost to be
confounded with the black of the pupil. In the European, the colour of
the iris is so strongly marked as to render at once perceptible whether
the person has black, blue, or gray eyes. There is nothing similar in
the case of the negro, where all parts of the eye are blended in the
same hue. Add to this that the white of the eye is always suffused with
yellow in the Negro, and you will understand how this organ, which
contributes so powerfully to give life to the countenance of the White,
is invariably dull and expressionless in the Black Race.”
To the Esquimaux, living in the constant glare of ice and snowfields, a
protective pigment is quite as necessary as to an African savage; hence
their eyes are equally black. But among other northern races, who are
less constantly exposed to the blinding rays of the sun, it suffices to
have coal-black pigment in the back part of the eye, as seen through the
pupil, while the iris need not be so absolutely opaque. This leaves room
for the action of Sexual Selection in giving the preference to eyes less
monotonously black. Our æsthetic sense craves variety and contrasts in
colour; and as the sense of Beauty originally stood in the service of
Love almost exclusively, it is to Cupid’s selective action that we
doubtless owe the diverse hues of the modern iris.
To what kind of an iris does modern Love or æsthetic selection give the
preference? Doubtless to that which has the deepest and most
unmistakable colour—to dark brown, or deep blue, or violet. One reason
why we care less for the lighter, faded tints of the iris is because
they present a less vivid contrast to the white of the eye; and another
reason, as Dr. Hugo Magnus suggests, lies in the disagreeable impression
produced in us by the difficulty of making out the exact character of
the various indistinct shades of gray, yellow, green, or blue.
The consideration of the question whether amorous selection shows any
further preference for one of its two favourite colours—dark brown and
deep blue—must be deferred to the chapter on Blondes and Brunettes.